Karal can tell that they're people who would admire one another.   It hurts - it feels like a betrayal of the people he loved and served all his life, except that yes, it was a tragic pointless wasteful war and he has a wider enough view now to see that they have all betrayed each other in allowing it to happen, and that doesn't hurt any less.  He could tell himself that they can all do better now, but they cannot all do better, Kadrich is dead-- 

--and he cannot think about that, right now. 

Leareth trusts him to make things better, and it would make nothing better to let this pain spread, instead of holding it in and trying to make something that isn't a pointless tragedy happen this time.  That thought is enough that he can try to live in the world that is so much larger than what he has known before, in which that death was not the most important thing in his life, in which what happens next matters more than everything he's lived through.  He had been half living in that world already, but he hadn't deliberately made the decision, and - making it, too, hurts, but it's a better feeling.  A release, of sorts - not from the pain, which will always be there, but from some bondage to it.  Unnoticed tension disappears from the set of his body, and he leans back and looks at Vanyel again - like at a good man he barely knows, rather than a distressing phantom.

This doesn't mean he has any idea what Leareth and Vanyel's many years of slow negotiation were about or what direction they could have usefully been leading in.  But he can start from where they are, he supposes.  And from normal human conversation, rather than pushing back into topics they cannot take too much of at once.

"At least say if you believe me, or if I should be trying to think through what to do if you don't."  He thinks the man believes him.  But trust works better when said out loud.

"And will you sit down, instead of standing over me all night?  I promise I won't try to stab you again."  A bit of a rueful smile, with that.

Vanyel blinks. Shakes his head, more in embarrassment than negation. 

"...I don't think you're trying to tell an elaborate lie. It's - bizarre, but I'm sure you also noticed that." Doesn't Leareth have people who work for him? ...Well, Karal didn't actually say they weren't with Leareth's people, just that Leareth is sick and can't talk, and it's not like anyone other than Karal can take Leareth's place in the dream to speak for him. 

"And - sorry." Self-conscious shrug. "Even if you did stab me, it's a dream. I figure Leareth was only willing to talk to me like this because I can't stab or, well, Final Strike, him." 

He can use the false magic that the dream gives him to shape a couple of stools for them, and put up a windbreak and a heat-spell. It's still not comfortable but it's less uncomfortable than sitting on the ground. 

He nods at the first reply, and appreciates the magical comfort, although he was already a lot more comfortable than what he's had to get used to recently.

"That sounds like him." 

He tilts his head curiously.  "Would you, if you could?"

What a horrifically unfair question

"...I'm not sure. I mean, I absolutely would have ten years ago, so the conversation wouldn't exactly have gone anywhere. But... I don't know." 

Shrug. "Probably I still would, if I did somehow have the chance?" Though Vanyel doesn't sound entirely convinced by his own words. "I mean. It's not like he's ever said he had stopped planning to invade Valdemar. Or explained why. ...I figure you know why but, um, obviously I don't expect you to just tell me, if Leareth thinks he had a good reason for not telling me." 

"I do know, and I don't think I should tell you."  He doesn't think it would make anything better, not now.  (And... Vanyel has clearly had enough horror without Karal adding to it.)

"I'm not even sure what I think of it myself, yet."  They don't have access to the records that would give him any chance of making sure that the awful idea makes sense the way Leareth claims it does - and even if it does, he still needs decide for himself whether he thinks it could possibly be right, to do something like that.  He said he would help Leareth get home, and he will, but he can still spend the rest of his life trying to convince him he's wrong.  "But... he really is trying to do the right thing, in his incredibly strange way."

He wonders if Leareth ever told Vanyel that, or if he's spent the last ten years maintaining his principle of never making himself sound any better than necessary.

...Leareth is not in fact sure he's made that claim to Vanyel in those words, but mostly because "doing the right thing" is - a pretty underspecified concept. Many people, maybe most people, are trying to do the right thing, and the thing they mean isn't at all what Leareth is trying to do, and - he doesn't want Vanyel to be confused.

A lot of Leareth's thoughts here are implicit and going by very fast, happening on a level more like intuition than his usual deliberate style of reasoning which is so badly impaired by the compulsion and their physical condition. There's something he's trying for and it probably won't work, most of the time it doesn't work, but - you have to reach for cooperation every time - the thing he's trying for won't work unless Vanyel actually understands, and the unlikely path to Vanyel actually understanding runs through Vanyel not being confused about who and what Leareth is. 

He's said a lot of things to Vanyel, and the important parts weren't any claims he made about himself, which Vanyel has no reason to take at face value and plenty of reason to suspect as manipulation - the important things are...things that are true the way math is true, things that Vanyel can hold up against the world and assess for himself. And he has, he thinks, seen that change how Vanyel thinks and acts in the world, Vanyel is already in many ways less...bound by an unreflected-upon code of honor...than the rest of the Heralds...

Snort. "Glad we can agree that Leareth is an incredibly strange person."

Vanyel looks past Karal at the horizon. "...I don't think I can take anything you say as - proof of what Leareth really wants - even if he can't hide who he is from you, how do I know he didn't just - use a compulsion to make you feel the way he wants you to feel?" Shrug. "But it's - information, I guess. ...And I do think - did already think - he probably wasn't lying to me that he - cares about his principles. In his own bizarre way." 

Leareth is probably right that that's the important goal, but Karal cannot convey any additional insights into the sorts of things that are true the way math is true.  He barely even knows any math - or any relevant facts about the world, since even Leareth remembers very few of them.  All he can do is... try to provide a second perspective on all their interactions.  Let all three of them know each other, to the extent that he can.  Things that are just true are important, but it is, also, important to know people.  Karal's own reaction to Leareth did not rely on anything but that, and he doesn't think it was wrong for it.

He chuckles and nods at Vanyel's first comment.  Then: "You know, that's a very good question, why didn't he do that...  Well, because he's the sort of person who wouldn't without a better reason," Karal has no illusions that Leareth wouldn't have done it if it was the only way to accomplish something very important, but not if he could get it in a more honest way, and not just for the sake of misleading Vanyel, leaving aside the part where he doesn't want to do that anyway.  "But also I... don't think compulsions work that way?"  He's not sure, but between watching this one work and catching Leareth's half-formed thoughts about the subject, he doesn't get the impression it would work.  (And if the Sunpriests could do that, a lot of the war would've looked different.)

It's not really that he expects to fully convince Vanyel, when he's sure of very few things himself - it's just that talking to him without aiming for anything in particular will let them get used to each other, and maybe let them find some things they didn't realize they needed to talk about.

... For instance if Vanyel is sure that compulsions do work that way, Karal would very much like to know that.  Less because he's worried about himself, and more because of what it'd mean about more complicated things that might be wrong with Leareth's mind.